1. Field of the Invention
The present invention relates to oral hygiene and specifically to methods of treating the oral cavity with a dental delivery systems such as toothpaste, masticables including chewing gums, dental floss or toothpicks, with improved cleaning, conditioning and antimicrobial properties, which provide the teeth with an impervious protective barrier. The present invention also relates to compositions and dental delivery systems having improved cleaning, conditioning, and antimicrobial properties, which provide the teeth with an impervious protective barrier. The present invention also relates to compositions and delivery systems useful for sealing and blocking dentinal tubules thus relieving pain and discomfort due to sensitivity. The present invention also relates to novel cationic surfactants especially suited for use in the present compositions, methods, and dental delivery systems.
2. Description of the Background
The oral care industry and health research communities have looked for many years for a way to interdict the attachment, propagation, growth or colonization of bacteria on teeth since adhered bacteria are the start of a pernicious chain of events leading to formation of home care-resistant plaque, calculus, and ultimately, tooth-loss. As people in developed countries live longer, dental care plays a larger role in overall health, and developing countries are becoming more aware of the importance of oral hygiene.
Dental plaque results when cariogenic bacteria (e.g., Streptococcus mutans) collect in colonies and form deposits on tooth surfaces. The presence of the bacteria and deposits is extremely detrimental to the health of the tooth for, if left unchecked, they may result in infected gingival tissue, the formation of dental caries and possibly periodontal disease. In extreme cases their presence may even result in the loss of teeth. Many attempts have been made to control or prevent both the occurrence of dental caries and the formation of dental plaque. For example, fluoride solutions or gels have been used. Treatment with these materials is typically performed in a dental office at periodic, but not frequent, intervals. Such treatments are primarily intended to render tooth enamel more resistant to the acid action caused by plaque. They do not, however, result in plaque control for an extended period since plaque reestablishes itself on the teeth shortly after ingestion of food.
Even when the frequency of application of such solutions and gels is increased only partial control has been shown. For example, studies wherein a fluoride-containing solution (1% fluoride concentration) was applied four to five times in the course of a year have demonstrated that this technique had only limited success due to the rapid reestablishment of plaque in the oral cavity. Moreover, the daily application of a fluoride gel by means of a custom-fitted polyvinyl mouthpiece for a period of twenty-one months also showed no substantial change in plaque formation among treated and untreated patients (see "Clinical Anticaries Effect of A Repeated Sodium Fluoride Application by Mouthpiece," Journal of the American Dental Association, vol. 75, Sep. 3, 1967, pages 638-644).
For long years the dental research community has sought to develop a way of sealing the teeth against access to dental surfaces by bacteria, acids and other deleterious materials. Good sealants have been developed and are now available, but they require professional application involving thorough cleaning and drying of each tooth prior to application of the sealant and the cost and availability of qualified professionals has meant that the benefits of this technology are not available to many people in the developed world and essentially to no one in the lesser developed countries.
Proper use of dental floss is necessary to clean the considerable area on the interproximal surfaces of teeth, which cannot be reached by the bristles of a toothbrush.
The purpose of using dental floss is:
1. to dislodge and remove any decomposing food material that has accumulated at the interproximal surfaces that cannot be removed by brushing; and PA1 2. to dislodge and remove as much as possible the growth of bacterial material (plaque) upon the teeth or the superimposed calculus that has accumulated there since the previous cleaning. PA1 (a) 0.25 to 25 wt. %, based on the total weight of (a) and (b), of a transfer agent; and PA1 (b) 75 to 99.75 wt. %, based on the total weight to (a) and (b), of a barrier material to teeth results in a prolonged reduction in the ability of bacteria to adhere to teeth. PA1 (1) The transfer agent stratum has dual functionality, being composed of materials having some molecular segments or parts of a polymeric chain which are positively charged and other such segments which exhibit hydrophobic characteristics. PA1 (2) Barrier Stratum: to the hydrophobic components of the transfer agent stratum, a hydrophobic, inert material (hereafter called the "barrier" material), such as a wax is adhered. The thickness of the barrier stratum is typically between about 1 and about 10 .mu.. PA1 (3) Anti-Bacterial function: within the barrier stratum may be blended therapeutic, hygienic, anti-sensitivity, including particulate materials or otherwise desirable materials which are released as they are exposed on the surfaces of the barrier stratum. One of the materials typically blended into the barrier material is a substance or substances shown to inhibit the attachment or otherwise defeat the propagation, growth or colonization of deleterious bacteria such as Streptococcus mutans, S. sobrinus, etc. As noted above the composition may further comprise other active agents. Any such substance is referred to hereafter as an "Active-Agent" or "A--A" material. PA1 I. Application of a composition of the present invention to teeth provides a continuous, hydrophobic, inert barrier which prevents acids, staining materials, (FIG. 9 shows several staining materials on an untreated surface on the left, 9a, compared with the same materials on a surface treated with a composition of the present invention on the right, 9b), food particles, bacteria and all other materials from gaining access to the treated dental surface and thus provides protection against all of the usual destructive processes--including the loss of fluorine by elution. In addition, these deleterious substances attach themselves less readily to the barrier than they do to unprotected tooth surfaces. PA1 II. Any bacteria or other debris which do attach to the protective barrier are easily removed by toothbrushing, pressure water cleaning, flossing and even by vigorous mouth rinsing since the amorphous barrier is easily cleaved or sheared, removing the outermost material but leaving some of its protective barrier remaining. Without such protection, bacteria which have attached themselves to the tooth surface soon become impossible to dislodge by toothbrushing or flossing and must be professionally removed. Since bacterial attachment begins to take place soon after each meal, the barrier is of great prophylactic significance. PA1 III. The barrier material readily fills and thus seals pits, fissures and cracks which are the favorite venues for bacteria colonization and plaque development. The barrier remains in place until mechanically removed from these pits, etc. and thereby provides protection which is even more extended in the vulnerable areas, since the barrier material is not removed from pits, fissures, etc. as easily as it is from smoother tooth surfaces in the ordinary course of abrasive action by the tongue, mastication of food, toothbrushing, etc. PA1 IV. By the addition to the barrier composition of an antibacterial material, 5-amino-1,3-bis(2-ethylhexyl)-5-methylhexahydropyrimidine, which is obtainable from Angus Chemical Co. under the trade name Hexetidine being an example of a most especially preferred active agent, bacterial attachment to the barrier surface is reduced by an estimated 90% or more, compared to the number and density of bacteria which attach to unprotected tooth surfaces. Of course, those bacteria which do attach are still easily removed by typical consumer activities such as toothbrushing and flossing. In addition, it appears that the hexetidine migrates or diffuses from the barrier material onto tooth surfaces which the barrier didn't reach, providing some protection to these hard to reach and most vulnerable areas. PA1 V. Importantly, the benefits of the present invention can be delivered by a broad range of application methods, e.g., toothpaste, chewing gum, masticable matrices other than traditional chewing gum, dental floss and tape, Q-tip.RTM.-like swabs, toothpicks, interdental appliances like STIMUDENTS.RTM., pre-coated toothbrushes, and any other applicators for consumer or professional use that one wishes to use. The only criterion is that it must be able to bring a waxy material into contact with dental surfaces.
The concept of the use of dental floss for cleansing interproximal spaces appears to have been introduced by Parmly in 1819 ("Practical Guide to the Management of the Teeth," Collins & Croft, Philadelphia Pa.). Parmly suggested the use of waxed silk to clean teeth of persons subject to gingival inflammation. Numerous types of floss were developed and used for cleaning, until finally in 1948 Bass established the optimum characteristics of dental floss (Dental Items of Interest, vol. 70, pp. 921-34, (1948)). Most floss sold at retail today is also "waxed" to assist penetration to interproximal regions; as the "cord" effect described by Bass makes the floss bundle difficult to force between closely spaced teeth.
From 1960 through 1962, numerous clinical studies reported that there is no clinical difference as to plaque removal and gingivitis scores between waxed and unwaxed dental floss. O'Leary in 1970, and Hill et al. in 1973, found no difference in the interproximal cleansing properties of waxed or unwaxed dental floss. This was reconfirmed in 1982 by Lobene et al. (Clinical Preventative Dentistry, Jan.-Feb. (1982)) who showed no significant clinical difference on plaque and gingivitis scores. Similar results. i.e., no clinical difference between waxed and unwaxed floss with respect to reduced gingival inflammation were shown by Finkelstein in 1979 (J. Dent. Res., vol. 58, pp. 1034-1039 (1979)). No differences in gingival health were shown by Wunderlich in 1981 (J. Dent. Res., vol. 60A, p. 862 (1981)). No differences in plaque removal were reported by Schmidt et al. in 1962 (J. Dent. Res. (1962)) with flosses of various types. Stevens in 1980, studied floss with variable diameters and showed no difference in plaque and gingival health. Carter et al., Va Dent. J., vol. 52, pp. 18-27 (1975), studied professional and self-administered waxed and unwaxed floss and found that both significantly reduced gingival bleeding of interproximal and gingival sulci. Unwaxed floss appeared slightly, but not significantly more effective.
In view of this clinical work, it is not surprising that most of the dental floss sold today is bonded and/or waxed. The "bonding" in the yarn industry today is used more to facilitate processing and production during floss manufacture and packaging than for "flossing" reasons. Since clinical tests show no difference between waxed and unwaxed floss, the floss industry has been comfortable with the yarn industry's propensity to use bonding agents in floss.
In any event, most people in the world do not floss their teeth. Instead, sticks or toothpicks are often used to clean their teeth.
Maetani et al, U.S. Pat. No. 2,504,228, describe a metallic dental casting coated with a PTFE coating. The PTFE coating is applied from a solution. The PTFE may also be applied from a suspension (an organosol) that may include other resins as well, such as, for example a silicone.
Lorch in U.S. Pat. No. 4,776,358 describes a flossing tape that carries its own supply of a dentifrice. The tape may be made of a confronting pair of laminae films that are microporous. The dentifrice is positioned between confronting surfaces of the two laminae, and the longitudinal opposite edges of the two laminae are sealed together. In use, the dentifrice flows out through the pores of the laminae. The laminae may be films of PTFE. The dentifrice is conventional, generally a commercially available material,
Blass in U.S. Pat. No. 4,996,056 describes coating a dental floss or tape with a mixture of wax and PTFE powder.
La Rochelle in U.S. Pat. No. 4,157,386 discloses a lozenge which coats the surfaces of the teeth and which contains fluoride ion, a polishing agent, and a vegetable oil.
Gaffar et al in U.S. Pat. No. 5,344,641 discloses a dentifrice containing an antibacterial agent, an antibacterial enhancing agent, a polishing agent, and a solubilizing agent. The antibacterial enhancing agent is an anionic film-forming material thought to attach to tooth surfaces thereby preventing bacterial attachment and enhancing delivery of the antibacterial agent to tooth surfaces.
Raaf et al in U.S. Pat. No. 4,169,885 discloses a filled capsule which has an outer hydrophilic active substance and an inner core containing a hydrophobic substance, a fluoride source and an antimicrobial substance. Upon consumption of the capsule, the hydrophilic substance is believed to fix the hydrophobic active substance to the teeth.
Hill et al in U.S. Pat. No. 5,165,913 discloses dental floss which contains a surfactant, silicone and a chemotherapeutic agent. The chemotherapeutic agent is delivered upon splaying of the floss. The surfactant and the silicone are believed to coat the teeth, provide a smooth feeling to the user, and prevent the attachment of bacteria.
Chang in U.S. Pat. No. Re 31,787 discloses an elution reducing dentifrice containing a membrane-forming material. Application of the membrane-forming material is believed to inhibit the elution of a previously applied therapeutic agent (i.e., fluoride).
Curtis et al in U.S. Pat. No. 4,528,182 and Crawford et al in U.S. Pat. No. 4,490,353 disclose an antiplaque dentifrice composition containing a quaternary ammonium compound, a betaine surfactant, polyethylene glycol and an abrasive. The presence of the betaine surfactant is believed to increase the foaming of the dentifrice and to prevent the deactivating of the quaternary ammonium compound.
However, none of these approaches or any other available product or technology has proven to be satisfactory since all prior attempts to produce a consumer-applied protective sealant have resulted in systems which apply a mono-layer--a single molecular layer --of material which is soon removed by chemical or mechanical action so that efficacy, if any, is of exceedingly short duration. Thus, there remains a great need for improved methods, compositions and dental delivery systems which are effective for the prevention of bacterial adhesion to teeth, exhibit antimicrobial properties and can be applied by traditional or acceptable means by the consumer as well as the professional to teeth which need not be dry or particularly clean.
A significant portion of the human population experiences pain or discomfort due to sensitivity of the teeth to heat, cold or pressure. Many products promise or provide short term relief but more lasting benefits have been elusive. Compositions and methods of the present invention may afford many sufferers longer term relief as dentinal tubules are occluded or effectively blocked more enduringly.